The purpose of this grant is to continue the study of infant color vision and related topics. In the coming five year period, temporal aspects of color vision, including the effects of temporal stationarity, flicker, and motion, will be studied, mostly in 2-month-olds. Three series of experiments are proposed. Series I: Photometry. Photometry is concerned with equating the brightness (technically, luminances) of lights that differ in color. Two methods used on adults--motion photometry and heterochromatic modulation photometry--will be adapted and used to establish infant luminance matches for red vs. blue stimuli. The tradeoff of rods (V-lambda) and cones (V- lambda) with stimulus luminance and temporal characteristics will be of particular interest. Series II: Color (chromatic) discriminations. In Series 2, the influence of stimulus velocity and flicker rate on chromatic discriminations will be studied. Temporal and motion contrast sensitivity functions (CSF's) for both luminance-modulated and chromatically-modulated (red/blue) stimuli will be determined. Comparisons of performance across motion vs. flicker will be made, and highly specific losses of chromatic discrimination for moving stimuli (a phenomenon recently found in adults) will be particularly sought. Series III: Chromatic axis asymmetries. In adult color vision, different color pairs (chromatic axes) have very different properties for sustaining specific aspects of perception (e.g. the minimal distinctness of borders (MDB's) and the perceived direction of motion of complex ("plaid") moving stimuli). These properties will be sought in infants.